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Патент USA US3087340

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April 30, 1963
- E. METZMEIER
3,087,330
FORCE MEASURING
Filed Aug. 4, 1959
4 Sheets-Sheet 1
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April 30, 1963
E. METZMEIER
3,087,330
FORCE MEASURING
Filed Aug. 4, 1959
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4 Sheets-Sheet 2
Jnve'nfor:
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April 30, 1963
E. METZMEIER
3,087,330
FORCE MEASURING,‘
Filed Aug. 4, 1959
4 Sheets-Sheet 3
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Eeu/A/ MErZHA-IIQQI
April 30, 1963
E. METZMEIER
3,087,330
FORCE MEASURING
Filed Aug. 4, 1959
Fig. 9
4 Sheets-Sheet 4
Fig. 10
87 M-J/M
United States Patent 0
3,087,330
Patented Apr. 30., 1963
2
1
amount of space. Furthermore, a measuring apparatus
of this kind must also be suitable for dealing with rela
3,687,330
tively large and rapidly succeeding variations in the
FORCE MEASURING
Erwin Metzmeier, Sodenerstrasse 24, Berlin
forces being measured, whereas on the other hand the
force-transmitting part must not be subjected to tilting
forces which falsify the measurement result and pre
Wilrnersdorf, Germany
Filed Aug. 4, 1959, §er. No. 831,584
8 Claims. (Cl. 73-140)
judice the working reliability of the apparatus.
The invention provides an apparatus for measuring
forces which takes these conditions into account. It takes
or backward propelling force exerted on water craft or 10 up scarcely any space in the direction of the force being
measured, makes it possible to carry out highly dynamic
aircraft by the driving mechanisms thereof.
measurements and prevents the occurrence of tilting
Apparatus used hitherto for the purpose speci?ed, such
stresses at the force-transmitting parts.
as hydraulic load-measuring cells, expansiommeasuring
According to the invention, these advantages are
strips, piezo-electric and magneto-electric transmitting
means and also optically or photo-electrically operating 15 achieved in that, more particularly for carrying out
dynamic measurements, there are provided two annular
devices, has the disadvantage of requiring a consider
springs whereof one acts from outside and the other
able amount of space and generally gave measurement
from inside on conical or spherical surfaces arranged ex
results of inadequate accuracy owing to the necessity,
ternally and internally respectively on the force-trans
unavoidable in most cases, of using a considerable num
ber of co-operatin-g transmitting elements whose overall 20 mitting part.
In this way, the invention provides an apparatus for
measuring accuracy was prejudiced by disturbing in?u
measuring
forces which takes up very little space and at
ences which varied locally and due to assembly.
the same time permits very great measuring accuracy
These disadavntages of the known apparatus are all the
and which consequently is particularly suitable for ?tting
more serious since the high standards as regards economi
cal operation which are expected for example of driving 25 in the driving mechanisms of water craft and aircraft.
The invention relates to an apparatus for measuring
forces, more particularly for determining the forward
mechanisms for water craft and aircraft need very ac
curate measurement of the forward or backward propell
ing forces which are exerted by such driving mechanisms
The invention can be carried into effect in a partic
ularly advantageous manner if the spring element is con
structed as an annular spring which is provided prefer
ably with at least one conical surface for receiving the
in the most diverse working conditions on water craft or
aircraft. At the same time, however, the space avail 30 force to be measured.
It is advantageous in certain cases if the spring ele
ment is constructed as a cup spring provided preferably
with at least one conical surface for receiving the force
space required, particularly for avoiding deformation
to be measured.
and vibration phenomena in the achievement of a me
If the apparatus is intended to be fitted in thrust bear
chanically satisfactory construction of the parts used for 35
ings having a plurality of thrust shoes arranged on their
transmitting these forces is in any case so great that, for
periphery (Mitchell bearing) according to the invention
example, the increase in the overall length of the thrust
able for accommodating apparatus used merely for meas
uring or controlling purposes is very limited. For the
the apparatus can be so constructed that the outer and/
or inner sides of the segment holders are provided with
of hydraulic load-measuring cells between a shaft collar
40 conical surfaces which bear on the conical inner and/ or
and the :bearing surfaces becomes unacceptable.
bearing of a ship’s driving shaft by the interposition
On the other hand, the highly competitive require
ments expected nowadays, for example, in respect of the
economical running of ships makes it absolutely necessary
to have a very accurate continual supervision of, more
particularly, the forward propelling force produced by
the driving mechanism under many different working con
outer surfaces of the annular or cup spring surrounding
them and/or surrounded by them.
In order to make the deformation of the annular spring
element measurable in a simple manner, the apparatus
45 according to the invention can be so constructed that the
annular or cup spring is provided at its periphery with
ditions, especially since for judging ship’s manoeuvres
one or more turns of an electric conductor which is in
ularly to the plate plane and whose. peripheries increase
tion in such a manner that it is arranged as a transmit~
sulated or is arranged in an insulated manner on the
there has recently been a change-over to using the pro
said spring, and whose electric resistance undergoes un
peller thrust and not the driving speed of rotation as the
50 der the in?uence of a mechanical deformation variations
basis.
which can be measured in a manner known per se.
It is already known in the case of load-measuring cells
With this construction of the apparatus, according to
for pit props to use annular springs on whose outer and
the invention the measuring operation can be carried out
inner rings expansion-measuring strips are arranged. By
in a particularly sensitive fashion if the measuring wire
connecting these measuring strips to appropirate elec
arranged on the periphery of the annular spring element
55
trical indicating devices, it was possible to measure in
is arranged in a labyrinth pattern in a manner known
this way the forces occurring in the pit props.
per se.
Expansion-measuring elements are also known wherein
In order to obtain a particularly economical or effec
a member in the shape of a circular plate and bendable
tive drive for propeller-driven water craft or aircraft,
under the ‘action of shearing forces is provided at both
sides with expanding rims which are disposed perpendic 60 the apparatus can be constructed according to the inven
or decrease when the plate is bent, and which are pro
vided with resistant material whose resistance varies with
ting means in an automatic variable-pitch propeller ar
rangement for maintaining the optimum angle of attack
in each case for every working state of the driving
the deformation of the expanding rims.
The aforesaid known load~measuring cells, however, 65 mechanism.
are not suitable for measuring forces in all cases.
Par
ticular dif?culty is found if the force-transmitting parts
are connected for example to the driving mechanisms of
In order to obtain a measuring accuracy which is not
prejudiced by temperature in?uences in the case of force
transmitting arrangements wherein different temperatures
In these cases it is necessary
occur, more particularly temperatures varying from the
exerted on the craft by the driving mechanisms without
the measuring apparatus having to take up a considerable
vention can be so constructed that a non-loaded ring or
water craft or aircraft.
to measure the forward or backward propelling forces 70 ambient temperature, the apparatus according to the in
a disc of the same material as the spring element used
3,087,330
3
4
.
for measuring is provided which is subjected to the same
surfaces against two measuring rings or annular springs
6, 6', the axial pressure exerted thereby being transmitted
to the bearing brasses 7 of the thrust bearing housing.
The annular spring 6 is opened in the radial direction
by the thrust force whereas the annular spring 6' hear
ing against the inner surface of the segment holder is
temperature ‘conditions as ‘the latter and is used in a
manner known per se for the compensation of the in
?uence exerted on the measurement result by the tem
perature of the spring element used for measuring pur
poses.
_
_ More particularly in cases Where it is desirable in the
compressed. The outer annular spring can be a continu
ous ring since its diameter is of such a size that it can
urement result uninfluenced by frictional forces occurring
be passed over the connecting ?anges which are not
between the‘ measuring ring and the force-transmitting 10 shown in the drawings. The inner ring can be divided
carrying out of dynamic measurement to have the meas
part, the apparatus according to the invention can be so
without prejudicing its action.
Bearing against the periphery of the two annular
constructed that in order to avoid friction between the
force-transmitting part and the ‘spring element one of
springs 6, 6' in several turns and in an insulated fashion
these two parts e.g. by means of per se known magneto
are electric conductors 8, 8' (see FIGURE 3) whose
strictive oscillation generator, is made to carry out elastic 15 electric resistance under the in?uence of the mechanical
oscillations in the direction perpendicularly to the force
deformation acting on them undergoes measurable varia
transmitting surface.
tions, and they are connected to a measuring instrument
The carrying-out of dynamic measurements, wherein
9 which is arranged outside the thrust bearing (FIG
the force being measured varies its direction, is facilitated
URES 3).
according to the invention in that two annular spring 20 ‘ Instead of resistance-measuring wires as illustrated in
elements, preferably annular springs, are provided one
the drawings, it is also possible to use expansion-measur
of which acts from the outside and the other from the
ing strips. Both the measuring wires 8, 8' which can
inside on conical or spherical surfaces arranged external
be arranged in labyrinth fashion in a known manner,
ly and internally respectively on the force-transmitting
part-
.
.
and also the expansion-measuring strips must be so con
25 nected in a manner known per se e.g. by gluing, to the
The measuring accuracy which can be attained with
surface of the measuring rings 6, 6' that they undergo
the apparatus is particularly advantageous more especial
the same deformations as the latter.
ly for carrying out dynamic measurements with a vary
In the journal and thrust bearing shown in FIGURE 4
ing force direction, if the apparatus is so constructed ac
for a steam turbine, there are arranged on the shaft 10,
cording to the invention that there is provided only one 30 adjoining both ends of the bearing member 11, thrust
annular spring element which is in contact, with some
collars 12, 12’ which bear on the thrust shoes 4 arranged
pre-loading, with the conical or spherical surface ar
loose in a circular recess v13, 13’. The thrust exerted by
ranged on the force-transmitting part.
the collars 12, 12' is transmitted through the shoes 4 to
Two examples of embodiment of the invention are
the segment holder 5 which bears by means of its conical
illustrated in the accompanying drawings, wherein:
FIGURE 1 is a longitudinal sectional view through a
thrust bearing for a ship’s driving shaft.
FIGURE 2 is a sectional view taken on the line II—II
35
surfaces against the two annular springs 6, 6' bearing
against the bearing member 11.
The arrangement of the measuring wires or measuring
strips on the annular springs is the same as in the preced
of FIGURE 1.
ing example.
FIGURE 3 shows the arrangement of measuring wires 40
The measurement result obtained for example by the
on annular springs adjoining a segment holder;
measuring instrument 9 (FIGURE 3) according to the
FIGURE 4 is a longitudinal sectional view through a
invention can be made independent of temperature in
journal and thrust bearing for a turbine subjected to pres
?uences acting on the measuring Wires 8, 8’ by providing
sure from both sides.
a compensating device. This consists e.g. of a ring 14
FIGURE 5 is a sectional view taken on the line V—V 45 which is arranged in the vicinity of the measuring ring 6
of FIGURE 4.
and preferably consists of the same material as the meas
FIGURE 6 is a sectional view through an apparatus
uring rings and is subjected to approximately the same
according to the invention provided with a temperature
temperatures as the measuring rings. This ring v14 is so
compensating device.
arranged that it is not deformed by the force being meas
FIGURE 7 is a sectional view through an apparatus 50 ured and that its thermal expansion is not prevented.
according to the invention provided with another con
For this purpose, it can be arranged, for example, in a
structional form of the temperature-compensating device.
groove 15 on the inner side of the collar 16 within the
FIGURE 8 is a sectional view through an apparatus
measuring ring 6 and concentric thereto, the width of the
according to the invention provided with a friction-re
groove ‘15 being greater than the width of the compensat
ducing device.
55 ing ring 14 including the measuring wires 17, 17' ?xed
thereto. The latter are also connected in a manner known
according to the invention provided with another form
per se with the measuring instrument 9v and are so ar
FIGURE 9 is a sectional view through an apparatus
of embodiment of the friction-reducing device.
ranged that the ‘temperature variations of the measuring
FIGURE 10 is a fragmentary elevational view of the
rings ‘6 and 6’ 'are compensated by the corresponding re
apparatus according to the invention provided with a 60 sistance variations of the measuring wires 17, 17’. In
friction-reducing device as illustrated in FIGURE 9.
order to guarantee as close temperatures as possible at
FIGURE 11 is an overall View of the apparatus ac
the measuring rings 6, 6’ and the compensating ring 14,
cording to the invention provided with a friction-reduc
the annular segment holder 5 can be provided between
ing device as illustrated in FIGURES 9 and 10'.
the individual segments 4 with holes 18 which are axially
65
In the example shown in FIGURES l and 2, 1 desig
directed and establish communication between the space
nates the housing of a per se known single-collar thrust
surrounding ‘the measuring ring 6 and the inner space 19
bearing used chie?y for ship’s drives, wherein a shaft 2
in which the compensating ring 14 is situated. These con
made in one piece is provided in the middle of the hear
necting holes 18 also give the lubricant ?lling the entire
.ing with a thrust collar 3. The thrust collar runs at both
70 bearing adequate access to the compensating ring 14.
sides on loose thrust shoes 4 (Michell thrust blocks),
As shown in FIGURE 7, the compensating ring can also
‘which bear against both sides of the thrust collar and
be so constructed that it is situated immediately adjacent
‘do not participate in the rotation of the shaft. The seg
the measuring Wires 8 on the periphery of the measuring
ment-shaped thrust shoes 4 are carried by segment hold
ring 6 in a groove 19 arranged therein which is so deep
lers 5 which bear with comically shaped outer and inner 75 that the compensating ring 14 can expand or contract
3,087,330
6
under the in?uence of heat, unhindered, in the radial di
rection. This construction guarantees obtaining a par
tension the outer spring radially outwardly, thrust means
disposed between the thrust collar and said tapered means
and operable to transmit the thrust of said shaft to said
ticularly effective compensating action.
When carrying out dynamic measurements, ‘wherein the
tapered means, electrically conductive expansion trans
direction of the force acting on the apparatus may vary, CI ducer means connected to said springs and comprising an
electric measuring conductor wound in at least one con
the measurement result in some circumstances is falsi?ed
tinuous turn about each spring though electrically in
by the action of the frictional forces occurring between
the measuring ring and the force-transmitting part. In
sulated therefrom and being operable to have the electric
conductivity varied by the expansion and respectively
order to avoid such disturbances, the apparatus can ac
cording to the invention be provided with means for re 10 contraction spring movements, and an electric circuit in
cluding said transducer means and a measuring instru
ducing friction. Such means can be for example devices
ment whereby said thrust may be measured by said instru—
for generating mechanical oscillations, preferably of rela
tively high frequency, which operate magnetostrictively,
ment.
2. A thrust gauge, as claimed in claim 1, said thrust
or electromagnetically or electrodynamically. Such oscil
lation generators can be arranged distributed symmetri 15 means comprising thrust shoes, said tapered means com
prising thrust shoe holders each having conical inner and
cally over the periphery of the measuring ring 6, as shown
outer surfaces engaging said groove.
in FIGURE 8. They then expediently consist of U-shaped
3. Apparatus according to claim 1, characterised by the
labyrinth arrangement of the measuring wire.
cores 20 which are preferably laminated in order to re
duce eddy current losses and which are ?xed with one
limb 21 to the bearing or any other ?xed par-t of the
4. A thrust gauge, as claimed in claim 1, and tempera
ture compensating means comprising an expandable ring
disposed in said groove outside the thrust path of said
machine and bear with their other limb 22, which carries
the ?eld coil 23, against the free end face of the measur
ing ring 6‘. When the coils 23 are supplied with alter
tapered means and composed of the same material as said
nating current, preferably of about 2,000 to 20,000 cycles
springs and comprised in said circuit.
quently undergoes elastic deformations of very small am
plitude and like frequency. These result in reducing the
uted uniformly along the periphery of said groove and in
vibration transmitting connection with said tapered means.
5. A thrust gauge, as claimed in claim 1, and friction
per second, the cores 20 transmit mechanical oscillations 25
reducing means comprising a series of oscillators distrib
of this frequency to the measuring ring, which conse
6. A thrust gauge, as claimed in claim 1, said annular
springs forming a ?rst mechanism, said tapered means
forming a second mechanism engaged by said ?rst mech
ting part. The friction between the measuring ring 6 and
anism, and means operable for reducing friction between
the force-transmitting part is thereby reduced in a manner
said mechanisms ‘comprising a vibration generator con
which is sui?cient for obtaining adequately accurate
nected to one of said mechanisms to impart thereto oscil
measurement results.
The friction-reducing device can be also constructed in 35 lations.
7. A thrust gauge, as claimed in claim 1, said bearing
the manner according to FIGURES 9 to 11, such that the
structure including a collar having a surface forming the
oscillation generators are distributed symmetrically over
bottom of said endless groove opposite said tapered means,
the periphery of a groove 24 arranged in the segment
an annular recess de?ned in said surface and extending
holder 5 itself, and consist of preferably laminated cores
throughout a fraction of said bottom and intercommuni
25 which extend in the radial direction and which bear
cating with said endless groove, and temperature compen
with their end faces on the outer and inner side walls of
sating means comprising an expandable ring having a por
the groove 24. They are secured against lateral displace
tion located in said annular recess and extending into said
ment, ?tted into the groove 24 with some pro-tension, and
carry at their periphery the coils 23. The oscillation gen 45 groove and being disposed concentrically with said annu
lar springs and spaced from said tapered means, the
erator-s 25, 23 can be distributed over the periphery of
friction between the conical inner surface of the measur
ing ring 6 and the conical surface at the force-transmit
width of said annular recess being in excess of the width
the groove in such numbers as to achieve an adequately
strong action on the inner and outer cones of the seg
of said expand-able ring.
8. A thrust gauge, as claimed in claim 1, said tapered
ment holder 5 by the oscillation generators to achieve
the reduction in friction between the measuring rings and
the force-transmitting part which is necessary for obtain
ing adequately accurate measurement results, more par
means having a series of holes terminating in said groove
opposite said expandable ring and channels intercommuni
eating with said grooves and terminating adjacent said
annular springs thereby establishing communication be
ticularly when carrying out dynamic measurements.
Many different forms of embodiment of the invention
are possible. The forms of embodiment described here
inbefore and illustrated in the drawings constitute merely
examples of constructional forms in which the invention
can be embodied.
What I claim and desire to secure by Letters Patent is:
1. A thrust gauge, for use in connection with a rotat
able drive shaft having a thrust collar and a non-rotating
bearing structure, the combination of two annular springs
supported by said bearing structure and de?ning there
between .a tapered outward ?aring endless groove, tapered
means engaged in said groove and operable when pressed
to compress the inner spring radially inwardly and to
tween the interior of said endless groove adjacent said ex
55
pandable ring and the space surrounding the annular
springs.
References Cited in the ?le of this patent
UNITED STATES PATENTS
654,103
1,998,450
2,544,567
Schrottke _____________ __. July 17, 1900
Davis _______________ __ Apr. 23, 1935
Rundell _____________ __ Mar. 6, 1951
468,238
790,057
Italy ________________ __ Dec. 29, 1951
Great Britian _________ __ Feb. 5, 1958
FOREIGN PATENTS
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